A variety of industrial processes are known for conversion of low boiling carbon-containing compounds to higher value products. For example, methanol to gasoline (MTG) is a commercial process that produces gasoline from methanol using ZSM-5 catalysts. In the MTG process, methanol is first dehydrated to dimethyl ether. The methanol and/or dimethyl ether then react in a series of reactions that result in formation of aromatic, paraffinic, and olefinic compounds. The resulting product consists of liquefied petroleum gas (LPG) and a high-quality gasoline comprised of aromatics, paraffins, and olefins. The typical MTG hydrocarbon product consists of about 40-50% aromatics plus olefins and about 50-60% paraffins.
U.S. Pat. Nos. 6,423,879 and 6,504,072 disclose a process for the selective production of para-xylene which comprises reacting toluene with methanol in the presence of a catalyst comprising a porous crystalline material having a diffusivity for 2,2-dimethylbutane of less than about 10−4 sec−1 when measured at a temperature of about 120° C. and a 2,2-dimethylbutane pressure of about 60 torr (about 8 kPa). The porous crystalline material is preferably a medium-pore zeolite, particularly ZSM-5, which has been severely steamed at a temperature of at least about 950° C. and which has been combined with about 0.05 to about 20 wt % of at least one oxide modifier, preferably an oxide of phosphorus, to control reduction of the micropore volume of the material during the steaming step. The porous crystalline material is normally combined with a binder or matrix material, preferably silica or a kaolin clay.
U.S. Pat. No. 4,088,706 describes a method for converting methanol to para-xylene. The method includes exposing a feed to a zeolite catalyst that is modified to include boron and/or magnesium.
U.S. Pat. No. 4,584,423 describes a method for xylene isomerization using a preferably alumina-bound zeolite catalyst containing a Group 2 or Group 12 metal. A feed containing a mixture of aromatic compounds including ethylbenzene is exposed to the catalyst for conversion of ethylbenzene to other compounds while reducing or minimizing the amount of xylene conversion.
U.S. Pat. No. 3,894,104 describes a method for converting oxygenates to aromatics using zeolite catalysts impregnated with a transition metal. Yields of aromatics relative to the total hydrocarbon product are reported to be as high as about 58% with a corresponding total C5+ yield as high as about 73%.
U.S. Patent Application Publication No. 2013/0281753 describes a phosphorous modified zeolite catalyst. The phosphorous modification reduces the change in alpha value for the catalyst after the catalyst is exposed to an environment containing steam. The phosphorous modified catalysts are described as being suitable, for example, for conversion of methanol to gasoline boiling range compounds.